Analyses of parasitic capacitance effects and flicker noise of the DAC capacitor array for high resolution SAR ADCs

Yue, Xicai; Kiely, Janice; McLeod, Chris

Abstract

Copyright © 2018 Inderscience Enterprises Ltd. This paper analyses the effects of parasitic capacitances of unit capacitors on the accuracy and the noise performance of the DAC capacitor array in a SAR ADC, showing that thermal noise of the array decreases while gain error is introduced. The gain error is almost independent of the number of bits, but the dynamic range of the high resolution ADC is severely reduced due to the gain error. The post-layout parasitic capacitance analysis of a 10-bit poly-poly array shows a large difference between the top-plate and bottom-plate parasitic capacitances so that the gain error can be decreased by 152 times when top-plates are connected together as the output node of the array. The switching transistors’ flicker noise calculation for a 10-bit and an 18-bit SAR ADC shows that flicker noise can be safely ignored for 10-bit 1MSPS SAR, but should be considered for the higher resolution SAR ADCs.

• Journal Article Type: Article
• Acceptance Date: Jul 24, 2017
• Online Publication Date: Nov 2, 2018
• Publication Date: Nov 30, 2018
• Deposit Date: Sep 26, 2017
• Publicly Available Date: May 2, 2019
• Journal: International Journal of Computer Applications in Technology
• Print ISSN: 0952-8091
• Electronic ISSN: 1741-5047
• Publisher: Inderscience
• Peer Reviewed: Peer Reviewed
• Volume: 58
• Issue: 4
• Pages: 259-266
• DOI: https://doi.org/10.1504/IJCAT.2018.095934
• Keywords: successive approximation register (SAR) ADC, DAC capacitor array, parasitic capacitance, thermal noise, flicker noise
• Public URL: https://uwe-repository.worktribe.com/output/904155
• Publisher URL: http://dx.doi.org/10.1504/IJCAT.2018.095934
• Additional Information: Additional Information : This is the author's accepted manuscript. The final published version is available here: http://dx.doi.org/10.1504/IJCAT.2018.095934.
• Contract Date: Sep 26, 2017